282 research outputs found

    Energy exchange between electron and molecular gases

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    Energy transfer between electron and molecular gase

    Direct observation of Levy flight of holes in bulk n-InP

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    We study the photoluminescence spectra excited at an edge side of n-InP slabs and observed from the broadside. In a moderately doped sample the intensity drops off as a power-law function of the distance from the excitation - up to several millimeters - with no change in the spectral shape.The hole distribution is described by a stationary Levy-flight process over more than two orders of magnitude in both the distance and hole concentration. For heavily-doped samples, the power law is truncated by free-carrier absorption. Our experiments are near-perfectly described by the Biberman-Holstein transport equation with parameters found from independent optical experiments.Comment: 4 pages, 3 figure

    Carotenoids and chlorophyll content in natural soap with addition of vegetative raw material

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    In the present study, we performed quantitative and qualitative determination of carotenoids and chlorophyll in five samples of natural soap with addition of vegetative raw material: Green tea, Chamerion angustifolium (L.) Holub, Trifolium pratense L., Alchemilla vulgaris L. and Urtica dioica L. There was developed the method of quantitative content of carotenoids and chlorophyll using spectrophotometry with analytical wavelength at 450 nm (carotenoids) and 667 nm (chlorophyll). Qualitative determination was carried out by the comparative TLC analysis. As mobile phases were used in the experiment following a mixed solvent of hexane-acetone (3: 1). Identification of carotenoids was carried out according to standard samples β -carotene and literature data

    Regenerative oscillation and four-wave mixing in graphene optoelectronics

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    The unique linear and massless band structure of graphene, in a purely two-dimensional Dirac fermionic structure, have led to intense research spanning from condensed matter physics to nanoscale device applications covering the electrical, thermal, mechanical and optical domains. Here we report three consecutive first-observations in graphene-silicon hybrid optoelectronic devices: (1) ultralow power resonant optical bistability; (2) self-induced regenerative oscillations; and (3) coherent four-wave mixing, all at a few femtojoule cavity recirculating energies. These observations, in comparison with control measurements with solely monolithic silicon cavities, are enabled only by the dramatically-large and chi(3) nonlinearities in graphene and the large Q/V ratios in wavelength-localized photonic crystal cavities. These results demonstrate the feasibility and versatility of hybrid two-dimensional graphene-silicon nanophotonic devices for next-generation chip-scale ultrafast optical communications, radio-frequency optoelectronics, and all-optical signal processing.Comment: Accepted at Nature Photonics, July (2012

    Learning from a fool: searching for the 'unmanaged' context for radical learning

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    Drawing on the existing theorizing of organizational learning from a radical perspective, this article attempts to problematize such notion of learning and position it within the existing organizational contexts informed by divergent types of rationality. The study scrutinizes these frameworks with a view to reflect on the potentiality for radical learning to occur within them. In this vein, the conceptual analysis of non-technical and non-marginal notions, namely, ‘spirituality’, ‘luck’ and ‘wisdom’, in different modes of rationality is conducted. This article demonstrates that since the conceptual inclusiveness is entailed by the specificity of sensemaking mechanisms, which these modes employ, the analysed notions can be approached as their litmus paper. The functionalist rationality types are found to be incommensurate with exigencies of the radical context for learning. In pursue of the conducive area for radical learning, the notions of unmanaged organization and the technology of foolishness provide the theoretical frame for the study, and their joint sensemaking context is discussed using examples. This unmanaged space driven by inclusive foolishness is recognized as one that enables the liminal sensemaking processes conducive for radical learning to occur

    Spirals of Spirituality: A Qualitative Study Exploring Dynamic Patterns of Spirituality in Turkish Organizations

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    This paper explores organizational spirituality, uncovers it as spiralling dynamics of both positive and negative potentialities, and proposes how leaders can shape these dynamics to improve the human conditions at the workplace. Based on case study of five Turkish organizations and drawing on the emerging discourse on spirituality in organizations literature, this study provides a deeper understanding of how dynamic patterns of spirituality operate in organizations. Insights from participant observation, organizational data, and semi-structured interviews yield three key themes of organizational spirituality: reflexivity, connectivity, and responsibility. Each of these themes has been found to be connected to upward spirals (inspiration, engagement, and calling) and downward spirals (incivility, silence, and fatigue). The study provides a detailed and holistic account of the individual and organizational processes through which spirituality is enacted both positively and negatively, exploring its dynamic and dualistic nature, as embodied in the fabric of everyday life and culture
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